On 06/11/18 23:20, Marc Orr wrote: > + x86_fpu_cache = kmem_cache_create_usercopy( > + "x86_fpu", > + fpu_kernel_xstate_size, This unfortunately is wrong because there are other members in struct fpu before the fpregs_state union. It's enough to run a guest and then rmmod kvm to see slub errors which are actually caused by memory corruption. The right way to size it is shown in fpu__init_task_struct_size but for now I'll revert it to sizeof(struct fpu). I have plans to move fsave/fxsave/xsave directly in KVM, without using the kernel FPU helpers, and actually this guest_fpu thing will come in handy for that. :) Once it's done, the size of the object in the cache will be something like kvm_xstate_size. Paolo > + __alignof__(struct fpu), > + SLAB_ACCOUNT, > + offsetof(struct fpu, state), > + fpu_kernel_xstate_size, > + NULL);
